--- a/tools/mkimage.h
+++ b/tools/mkimage.h
@@ -42,7 +42,7 @@ static inline ulong map_to_sysmem(void *
 }
 
 #define MKIMAGE_TMPFILE_SUFFIX		".tmp"
-#define MKIMAGE_MAX_TMPFILE_LEN		256
+#define MKIMAGE_MAX_TMPFILE_LEN		1024
 #define MKIMAGE_DEFAULT_DTC_OPTIONS	"-I dts -O dtb -p 500"
 #define MKIMAGE_MAX_DTC_CMDLINE_LEN	2 * MKIMAGE_MAX_TMPFILE_LEN + 35
 
